Space farming: Plant hormones might make it possible

Science fiction has brought us innumerable tales of cool things happening in outer space, from giant battles waged between super-speeding spaceships to the exploration of exotic, unknown planets in distant galaxies. These stories might pass over some of the more mundane facets of futuristic space life, like how our heroes eat and survive, but it doesn’t make it any less exciting when we step closer to them in real life.

Plant biologists from the University of Zurich have found that a certain hormone found in plants may hold the key to allowing them to grow in low nutrient and low gravity zones. This could open the door for future studies into the possibility of one day developing farming operations away from our home planet.

That hormone, strigolactone, supports the symbiosis between plant roots and fungi, which encourages plant growth, and could be effective even in challenging conditions (like the atmosphere of the moon, for example). This symbiosis is called mycorrhiza, and in this process, the fungus supplies the plant roots with additional water, nitrogen, phosphates and trace elements from the ground. In return, the fungus accesses sugar and fat produced by the plant. Strigolactone, secreted by the roots, facilitates mycorrhization, ultimately increasing plant growth even in soil that is low in nutrients.

There’s one stumbling block, though. A lack of gravity can impede mycorrhization. The researchers know this because they tested it out — they grew petunias alongside fungi in simulated low gravity conditions. They found that yes, microgravity reduced the amount of nutrients absorbed by the flowers. However, the plants that secreted high levels of strigolactone, and fungi that had been treated with a synthetic strigolactone hormone, were able to thrive in low-nutrient soil despite the gravity conditions.

Petunias, as members of the Solanaceae family, serve as models for other plants, including tasty ones like potatoes, tomatoes and eggplants. So, if petunias succeed in space, theoretically, so can some of our favorite veggies.

While we’re still rather far away from setting up colonies on the moon for many, many reasons, this study shows that maybe, on the distant day when you settle down to live in a space pod 238,900 miles away from home, you can tend to a little vegetable garden out back.